Thanks for keeping my invitation open?

I sent a meeting invite email to my client.Since they were on busy schedule they replied me this time we can't make it but we welcome the opportunity for you to demo your project portfolio the next time you are around. I want to send him a reply for keeping the meeting opportunity alive.

Can I send 'Thanks for keeping my invitation open/ailve?'. or is there any better way to write a thanks email. Help me to write a email